205421139 has 48 divisors (see below), whose sum is σ = 371314944. Its totient is φ = 106315200.

The previous prime is 205421131. The next prime is 205421201. The reversal of 205421139 is 931124502.

205421139 is a `hidden beast` number, since 2 + 0 + 542 + 113 + 9 = 666.

It is not a de Polignac number, because 205421139 - 2³ = 205421131 is a prime.

It is not an unprimeable number, because it can be changed into a prime (205421131) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 319152 + ... + 319794.

It is an arithmetic number, because the mean of its divisors is an integer number (7735728).

Almost surely, 2^205421139 is an apocalyptic number.

205421139 is a deficient number, since it is larger than the sum of its proper divisors (165893805).

205421139 is a wasteful number, since it uses less digits than its factorization.

205421139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1128 (or 1125 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 205421139 is about 14332.5203296559. The cubic root of 205421139 is about 590.0403486722.

The spelling of 205421139 in words is "two hundred five million, four hundred twenty-one thousand, one hundred thirty-nine".